For Adam Levine, being a coach on The Voice entails more than just mentoring musicians and standing on chairs. It’s a battle round that never ends when it comes to defending NBC's singing competition and the reputation of his fellow coaches.

When confronted with criticisms at a New York press event on Friday, the Maroon 5 singer didn’t hesitate to defend his fellow coach Christina Aguilera against her worst body image critics.

“People shouldn’t say those kind of things because, f--- you. It’s like, come on guys, grow up,” he told reporters. “The one thing about the culture right now – celebrity culture particularly – that is so ugly is [that] people feel like they can just say nasty things about other people…she gets a lot of it. It pisses me off. Of course I have her back, of course I defend her.

“Everyone’s so obsessed with trying to end bullying and ‘It Gets Better’ and this whole thing. Meanwhile, on one hand they’re saying that, and then doing things like that – that’s bullying," he added.

The singer, who can be currently seen on NBC's third season of The Voice, added that he felt "it’s none of anybody’s business what anybody does, unless they want to get into it and come out and talk about."

Contrary to what’s been aired in previous seasons, Levine asserted that his relationship with Aguilera is nothing but friendly, complete with the banter that fills familial bonds.

“The fights that everyone thought we were having were fictional -- we never hated each other, we never were having some sort of secret battles that everyone thought we were having,” he explained. “They were silly bickering things that brother and sister would do, it’s not nearly what everybody thought…we were always just messing around, it was never serious. We’re all good, Christina and I.”

Last season, the banter between Levine and Aguilera was escalated by the controversial song choices of Levine’s finalist, Tony Lucca. Some critics also argued that the former Mickey Mouse Club member was advanced to continue the Twitter feuds and boost ratings. Levine stated that everything onscreen between the coaches is entirely authentic.

“Nothing is scripted -- there are no gags, there are no premeditated ‘let’s get ratings by doing some stupid shit’ -- that doesn’t happen on our show,” he said. “No one ever feels like we’re putting on a show; we just feel like we’re just coaching these amazing singers and having a lot of fun.”

Fellow coaches aside, critics of the NBC singing competition have also jabbed that the show has yet to produce a musician with a real radio hit – a point supported by the fact that season one winner Javier Colon and Universal Republic Records parted ways in June.

“When we started, that was an interesting moment because the coaches didn’t know what this was, or what it was gonna be. Javier didn’t know what it was gonna be. So when you think about it, he had nothing to lose, no nerves," he said.

As Colon’s coach, Levine admitted that the newness of the show altogether did – and still does – prevent the winners from breaking out beyond The Voice platform.

“I think that we can [produce a breakout winner], in fact, I’m sure that we can do it. I think that we’re gonna have to just retweak how we bridge that gap,” he said of transitioning winners from TV show contestants to working musicians. “Honestly we haven’t done it yet."

“I think eventually, The Voice is gonna have to launch somebody into the stratosphere for the show to continue to be taken seriously…It would be really nice to have somebody emerge from the show and become what we all want them to become,” he added.

Levine saluted American Idol for delivering the music of their contestants to newfound fans so effectively, especially the tracks of one winner in particular.

“Kelly Clarkson really, in my opinion, solidified the show’s credibility and kept the show afloat the whole time, because she was the first person to win,” he said of the Grammy-winning artist. “It’s not like I watch American Idol all the time, but we all knew where she came from and what she’s achieved has been remarkable. That doesn’t happen every day. It’s being lucky, it’s being prepared. It’s being at the right moment at the right time.”

However, though The Voice has yet to emerge with a chart-topping singer, Levine noted that the show has still stayed true to values that greatly differ from Idol and The X Factor.

“When I sat with [executive producer] Mark Burnett and he pitched the idea of the show, the first question we all had -- or not a question but more of a demand -- was we’re not gonna make fun of these people," he said. "We’re not gonna sit there and criticize them in a mean way, in a nasty way. We’re not gonna make people feel bad about themselves, there’s just no point, it doesn’t make any sense to us to ever intentionally hurt somebody’s feelings."

"That’s the biggest difference – obviously, there’s the turning of the chairs and the ‘gimmicks’ that Randy Jackson so lovingly refers to, but I think there’s just a really good, genuine positive feeling that the show exudes that people really respond to.”